1. Field of the Invention
The present invention relates to a debug device, in particular, to a debug device for embedded systems and a method thereof.
2. Description of Related Art
Inside a computer system is installed a Basic Input/Output System (BIOS), which is responsible for performing the Power-On Self-Test (POST) procedure to the computer system. It is possible to assign a code to this procedure at each test point, so as to output to a specific input/output (I/O) port (e.g. I/O port 80), and such codes represent respectively a corresponding failure reason.
Hence, the current method for debugging the BIOS of a computer system is to link to the Peripheral Component Interconnect (PCI) or Industry Standard Architecture (ISA) interface on a computer motherboard through a debug card, in which such a debug card provides the display circuit, and when the BIOS performs the POST procedure and a hardware error occurs, the debug card can acquire the code of the corresponding test point for the hardware failure during the POST procedure via the connected interface, and display this code on the display circuit in the debug card, such that related technicians can be aware of the computer hardware failure and perform a debug process by means of the displayed code on the debug card.
However, for embedded systems, there is no BIOS installed inside, which is different from computer systems. Hence, when debugging an embedded system a method as described above for computer systems cannot be used. Besides, the processors used in embedded systems may differ from those in computer systems since processor vendors adopt various interfaces, and thus the entire development of embedded systems could be inevitably full of difficulties and challenges.
Although the embedded system implemented by means of the present Marvell PXA320 processor can perform single-step debug through RS-232 transmission, this approach simply displays the instructions currently executed by the embedded system onto a display interface, whereas in terms of debugging, it is impossible to pinpoint the location of hardware failure in the embedded system through the displayed instructions.